This invention relates to oscillating separators for separating unhulled rice and unpolished rice from each other after hulling rice, and more particularly, a rotatively oscillating separator for separating unhulled rice and unpolished rice from each other by rotatively oscillating a cone-shaped separating plate.
The applicant has proposed in Japanese Patent Application Heisei 11-156994 a rotatively oscillating separator for separating mixed rice into unhulled rice and unpolished rice by rotatively oscillating a cone-shaped separating plate composed of a plurality of segments. This rotatively oscillating separator comprises a vertical rotating shaft, a drive for rotatively driving the shaft, a plurality of eccentric portions on the rotating shaft, the eccentric shaft portions being offset a predetermined distance from the axis of the rotating shaft, circular separating vessels each rotatably mounted on each of the eccentric shaft portions and having a cone-shaped separating plate contained therein, retaining means for preventing the separating vessels from freely rotating, and means for adjusting an angle of inclination of the separating plate segments. There is provided a level sensor for sensing the thickness of a layer of mixed rice on the separating plate, an outlet from the sensor being sent to a controller to control the angle adjusting means for the separating plate segments, thereby maintaining the layer of mixed rice at a predetermined thickness.
The rotating oscillating separator of this type has a disadvantage that each of the separating vessels requires the use of angle adjusting means for the separating plate segments, this resulting in increase in manufacture costs. Since the adjusting means is disposed below the separating plate, the two adjacent separating plates are required to have enough space therebetween to accommodate the adjusting means. This makes it difficult to arrange the entire rotatively oscillating separator into a compact configuration.
Japanese Utility Model Publication Sho 60-36399 discloses a grain oscillating separator comprising grain separating plates inclined laterally, rocking arm means for oscillating the separating plates, and means for varying an rocking angle xcex8 2 of the rocking arm means on the upstream side in the lateral direction of the separating plates, without varying an angle of inclination xcex1 of the separating plates. The variation of rocking angle makes it optimum to separate the mixed rice into unhulled rice and unpolished rice while the mixed rice flowing longitudinally on the separating plates. However, this arrangement can not be applied to cone-shaped separating plates.
An object of the invention is to provide a rotatively oscillating separator of the type which rotatively oscillates separating vessels each having a cone-shaped separating plate, comprising oscillatory angle adjusting mechanisms for varying an oscillatory angle in rotative oscillation of the separating vessels.
A further object of the invention is to provide a rotatively oscillating separator including a plurality of separating vessels arranged in a compact and stacked relation.
These objects of the invention can be achieved by providing a rotatively oscillating separator comprising at least one separating vessel having a raised peripheral portion and a cone-shaped separating plate disposed in the vessel, and drive means for rotatively oscillating said separating vessel, mixed rice consisting of unhulled rice and unpolished rice being fed onto the separating plate in the separating vessel at a given location to separate the unhulled rice and the unpolished rice from each other, the unpolished rice being discharged through the raised peripheral portion of the vessel, and the unhulled rice being discharged through the central bottom of the separating vessel, characterized in that said drive means comprises a plurality of oscillatory drives provided at locations equi-angularly spaced around the separating vessel, said oscillatory drives each being upwardly inclined and operatively connected to the raised peripheral portion of the separating vessel to support it, said oscillatory drives being sequentially actuated at predetermined phases of delay to generate oscillatory motion to be imparted to the separating vessel, said each oscillatory drive including an oscillatory angle adjusting mechanism for retaining the oscillatory drive at the upward inclination and for varying an oscillatory angle in the rotative oscillation of the separating vessel.
As mixed rice is fed onto the separating plate of the separating vessel during rotative oscillation of the separating vessel, unpolished rice which is small in grain size and is great in specific gravity, is carried on the separating plate towards the raised peripheral portion of the separating vessel under the action of centrifugal force to exit the separating vessel through an unhulled rice discharge port. The unhulled rice which is large in grain size and less in specific gravity, slips off the separating plate so that it passes through the central portion of the separating plate. In case that the coefficient of friction, moisture, and specific gravity of rice as in different kinds of rice, take place, change, the oscillatory angle adjusting mechanisms may be operated to vary the angle of oscillation in the rotative oscillation of the separating vessel, thereby separating the mixed rice into unpolished rice and unhulled rice on the separating plate under an optimum condition.
In a preferred embodiment of the invention, each oscillatory drive is provided in a support frame pivotally connected to a framework of the separator by means of pivot pins and includes a motor, a gearbox for transmission of rotation from the motor, a driving shaft having at its top a crank-pin and connected to an output shaft of the gearbox, a oscillatory plate having an eccentric shaft and rotatably connected to the crank-pin, and means for preventing the oscillatory plate from revolving together with the crank-pin, and further comprising means for operatively connecting said oscillatory drive to said separating vessel, said means including a connecting member resiliently connected to the raised peripheral portion of the separating vessel and having mounting hub, and a follower rotatably connected to said eccentric shaft. Each of said oscillatory angle adjusting mechanisms includes an adjusting screw mechanism for rotating the support frame around the pivot pins to vary the inclination of the support frame. Each adjusting screw mechanism includes a internally threaded element freely movably mounted in the support frame, a vertical adjusting screw rod rotatably mounted in the framework for the rotatively oscillating separator and having a externally threaded portion threaded into the internally threaded element, and a hand-wheel for rotating the adjusting screw rod.
As the hand-wheel is rotated, the action of the screw between the external threads of the adjusting screw rod and the internally threaded element permits the support frame to be rotated around the pivot pins, thereby varying the angle of inclination of the oscillatory drive. Thus, the oscillatory angle of the separating vessel can be quickly and readily adjusted.
In a further preferred embodiment of the invention, the adjusting screw mechanisms include a rotation transmitting mechanism including sprockets on the adjusting screw rods and a chain engaged around the sprockets to rotate the adjusting screw rods in a synchronized relation.
In another embodiment, each adjusting screw mechanisms includes a internally threaded element rotatably mounted in the framework, a support element having an enlarged through-hole formed therein, and rotatably mounted in said support frame, an adjusting screw rod extending through said enlarged through-hole and having an externally threaded portion threaded into said internally threaded element, and lock nut means for fixedly holding said adjusting screw rod in place. With the lock nut means loosen, the adjusting screw rod is rotated to move it relative to the internally threaded element, thereby varying the angle of inclination of the oscillatory drive. Thus, the oscillatory angle of the separating vessel can be quickly and readily adjusted.
In a further preferred embodiment of the invention, there are provided a plurality of separating vessels disposed in a vertically stacked relation, a plurality of sets of upper and lower oscillatory drives are provided at locations equi-angularly spaced around the separating vessels, said upper and lower oscillatory drives of each set, are operatively connected through said connecting member and resilient joints to said separating vessels and include a common oscillatory angle adjusting mechanism for retaining the oscillatory drives at the upward inclination and for varying an oscillatory angle in the rotative oscillation of said separating vessels.
In a still further preferred embodiment of the invention, there are provided a plurality of separating vessels disposed in a vertically stacked relation, a plurality of sets of upper and lower oscillatory drives are provided at locations equi-angularly spaced around the separating vessels, each of said upper and lower oscillatory drives of each set, is operatively connected through said connecting member and resilient joints to said stacked separating vessels and includes an individual oscillatory angle adjusting mechanism for retaining the oscillatory drive at the upward inclination and for varying an oscillatory angle in the rotative oscillation of said separating vessels.